Elastic pedal-crank for cycles.



.A. WALTER.

= ELASTIC PEDAL CRANK FOE OYGLBS.

APPLICATION FILED JULY 24,1911.

Patented Apr. 2, 1912. I

ALFRED WALTER, 0F STIR-AUPITZ, GERMANY.

ELASTIC PEDAL-CRANK FOR CYCLES.

Specification of Letters Patent.

Application filed July 24, 1911.

Patented Apr. 2, 1912.

Serial No. 640,299.

To all whom it may concern Be it known that I, ALFRED WALTER, a subjectof the King of Prussia, residing at Straupitz, in the Kingdom ofPrussia, Germany, have invented certain new and useful Improvements inan Elastic Pedal-Crank for Cycles, of which the following is aspecification.

This invention relates to pedal cranks for cycles which are constructedin such a manner that the pedal crank is connected with the chain wheelthrough the intermediary of a helical spring. This arrangement offersthe advantage that the cyclist has to use less energy than at present,and that the corresponding parts of the cycle are not as quickly worn asis the case at present.

In the accompanying drawings the inven tion is shown.

Figure 1 represents in elevation a cycle with the improved device. Fig.2 shows the chain wheel and crank in cross section. Fig. 3 is a frontview partly in section of Fig. 2. Figs. 2 and 3 are shown on a largerscale than Fig. 1.

The pedal crank c is connected with the chain wheel d through theintermediary of a helical spring a, one end of which is fixed to a pineof the chain wheel d, its other end being fixed to a lateral extensionI) of the crank- 0. The hub f of the chain wheel 01 is screwed upon theend of the axle g. This hub f has two radial pins h adapted to engagewith an inner groove i of the hub of the crank a which is looselymounted upon the hub of the chain wheel. The hub of the crank has twoindentations 70 which serve for permitting the insertion of the lateralpins 72. of the chain Wheel hub into the internal groove 5 of the crankwhen the device is being put together. The ends of the helical spring aare fixed to the chain wheel and to the lateral extensions 6 of thecrank by means of screws 6 0 respectively.

The device operates as follows: If the cyclist pedals, the helical.spring a is put under tension before the crank 0 draws the chain-wheel dalong. It is evident that the second crank Z is mountedupon the axle 9through the intermediary of a helical spring m, the inner end of saidhelical spring being fixed to a lateral extension of a bush n screwedupon the inner end of the axle g.

I claim:

An elastic crank for cycles comprising in combination with the axle ofthe wheel, the

chain wheel keyed upon said axle by means of a hub, a bush screwed uponthe other end of said axle, a lateral extension of said bush, an outerpedal crank, a hub at the upper end of said outer pedal crank looselymounted upon the hubof the chain wheel and having an inner annulargroove and two radial arms projecting from the hub of the chain wheelengaging with said inner grooves, a lateral extension of the crank and ahelical spring surrounding the hub of the crank and fixed with one endto the chain wheel, and with the other end to the lateral extension ofthe crank, substantially as described and shown and for the purpose setforth.

In witness whereof I have hereunto set my hand in the presence of twowitnesses. v ALFRED WALTER. Witnesses:

RUD. SCHMIDT, LEM S. KATZ.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents.

Washington, D. G.

